EP0456245B1 - Ignition system for a heater using a fuel - Google Patents
Ignition system for a heater using a fuel Download PDFInfo
- Publication number
- EP0456245B1 EP0456245B1 EP91107574A EP91107574A EP0456245B1 EP 0456245 B1 EP0456245 B1 EP 0456245B1 EP 91107574 A EP91107574 A EP 91107574A EP 91107574 A EP91107574 A EP 91107574A EP 0456245 B1 EP0456245 B1 EP 0456245B1
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- EP
- European Patent Office
- Prior art keywords
- ignition system
- glow
- flame
- heater
- ignition device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D3/00—Burners using capillary action
- F23D3/40—Burners using capillary action the capillary action taking place in one or more rigid porous bodies
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/14—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermo-sensitive resistors
- F23N5/143—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using thermo-sensitive resistors using electronic means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
- F23Q7/001—Glowing plugs for internal-combustion engines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2227/00—Ignition or checking
- F23N2227/38—Electrical resistance ignition
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2229/00—Flame sensors
Definitions
- the invention relates to an ignition device for a fuel-operated auxiliary vehicle heater according to the preamble of patent claim 1
- a rod glow plug is provided as the ignition device for a fuel-operated heating device, in which the glow rod serving as the glow electrode also forms an ionization electrode, which is used for flame monitoring.
- a protective tube is provided in the case of a glow plug, which forms the ionization electrode. If the rod glow plug is used for flame monitoring using the ionization principle, additional devices must be provided on the rod glow plug, which act as an ionization electrode for flame monitoring. Therefore, the usual design of a glow plug must be changed and a glow plug especially suitable for ionization flame monitoring must be manufactured.
- a glow plug for internal combustion engines which is designed as a rod glow plug.
- This glow plug has a ceramic carrier on which a heating element similar to a conductor track is applied.
- the embodiment of a glow plug described there is also suitable for arranging an overheating protection (PTC resistor) and / or a voltage limiter (varistor) in the connecting leads of the heating element. There is no flame monitoring.
- a flame detector as a flame detector device, which protrudes into the combustion chamber of the heater.
- Such flame monitors not only interfere with the flame formation in the combustion chamber, but are also very sensitive to faults, since they must always be in the flame zone during combustion.
- DE-A-28 02 625 and 26 41 274 are glow ignition devices specified, in which PTC resistors are used as protection against overheating, the operating state in the second-mentioned publication being able to be detected via the optical glow pattern in a filament ignition device with a PTC resistor.
- the invention has for its object to provide an ignition device for a fuel-operated heater of the generic type, by means of which energy-saving ignition and reliable flame monitoring is made possible without an additional flame detector component.
- an ignition device for a fuel-operated auxiliary vehicle heater is distinguished on the one hand by the fact that the glow element has a PTC behavior, so that its resistance to flame formation is additionally increased.
- the PTC behavior of the glow element such as a tungsten glow element, is thus used to carry out flame monitoring during the glow process and also later.
- the resistance increases with the temperature of the material.
- This temperature range is in the invention Ignition device selected so that when a flame forms in the combustion chamber of the heating device, the resistance of the glow element to the glow process of the ignition device increases and a steep increase in the resistance of the glow element is recorded.
- Tungsten has proven to be the preferred material for the glow element, which has a PTC behavior if a rod glow plug is provided as the ignition device.
- the flame monitoring can take place without additional measures on the glow plug or an additional component, such as a flame monitor, so that the flame formation in the combustion chamber is not disturbed by additional components protruding into the combustion chamber.
- there is also no component in a burner of a fuel-operated heating device which simplifies the manufacture of the same and can shorten the burner dimensions of the heating device.
- a constant current is applied to the glow element in order to detect the voltage drop due to the additional increase in resistance that occurs during flame formation.
- a circuit can be used for flame monitoring, for example, because when a flame is formed due to the increased temperature on the glow element, the resistance of the glow element suddenly increases and a voltage drop occurs when a constant current is applied, which is then used for evaluation by a control device of the heater via appropriate signal processing devices can be used to trigger appropriate switching operations when a flame has formed in the combustion chamber of the heater.
- This constant current is applied in the glow pauses of the ignition device, which is obtained, for example, when the glow ignition device is controlled by means of a glow contact relay. Therefore, in the design according to the invention the ignition device essentially only to take circuitry measures with regard to the implementation of flame monitoring, which can be integrated into the control device of the heater. This reduces the amount of components involved in the manufacture of such a heater.
- the ignition device is designed such that when an additional resistance increase of the glow element occurs, i.e. during flame monitoring by means of the ignition device, a shutdown of the glow operation of the glow ignition device is triggered, since a flame is now present in the combustion chamber for starting the burner operation of the heater.
- the ignition device can also be switched off automatically by utilizing the PTC behavior of the glow element.
- the design of the ignition device according to the invention also permits constant monitoring of the combustion operation if the current signal to the ignition device is applied in a constant or clocked manner, so that continuous flame monitoring can also be carried out while the heater is in operation.
- the current signal can preferably be significantly smaller than that required for the actual glow operation.
- the flame monitoring can thus be used both in the glow phase of the glow ignition device, if it is used for its intended purpose as an ignition device, and in the combustion mode, so that the combustion behavior can be detected and monitored by means of appropriate evaluations.
- the energy supplied to the ignition device can be reduced if the ignition device is heated by the flame formation and therefore the electrical energy requirement for keeping the temperature of the ignition device constant is lower.
- the respective sizes are component-specific.
- the ignition device is switched off when the decrease in energy consumption determined on the basis of the PTC behavior of the glow element falls below a predetermined preset value.
- a stick glow plug can be used as the ignition device, which has a glow element, such as a filament, embedded in a ceramic mass. Tungsten, which has a pronounced PTC behavior, is particularly suitable as the material for the glow element or the filament.
- the burner is formed by an evaporation burner 1, which has an absorbent body 2, such as a fleece, on a carrier, which is arranged in a combustion tube 3, which delimits a combustion chamber 4.
- Liquid fuel is supplied to the evaporative burner 1 via a fuel feed line 5.
- a rod glow plug 7 is provided as an ignition device designated overall by 6, which goes through the carrier and the absorbent body 2 of the vaporization burner 1 and projects into the combustion chamber 4.
- the rod glow plug 7 has, for example, a filament 8 as the glow element, which is preferably made of tungsten and which is embedded in a ceramic mass 9.
- the glow plug 7 is operated in the glow phase by means of a glow clock relay or transistor in such a way that the glow element 8 embedded in the ceramic mass 9, like the filament, serves as a glow element, so that the glow plug 7 is connected to an air / fuel prepared for the ignition of the evaporative burner 1 Mixture is heated to suitable temperature.
- This suitable temperature or target temperature is approximately in the order of 1100 ° C.
- a constant current I is applied to the glow element 8 of the glow plug 7 during the glow pauses, ie the clock breaks of a glow clock relay 10. If a flame has formed in the combustion chamber 4, the rod glow plug 7 and thus the glow element or the filament 8 thereof are additionally heated by the flame temperature, and due to the PTC behavior of the glow element 8, their resistance increases additionally.
- This additional increase in resistance creates a voltage drop in the line section with constant current, which is used for flame monitoring.
- This voltage drop can then be used via an evaluation device (not shown) in order to trigger corresponding switching operations via a control device (not shown) of the heater. Even if this voltage drop does not occur and therefore no flame has formed in the combustion chamber 4, corresponding switching operations can be triggered as in the case of a conventional additional flame monitor.
- a control circuit 11 of the glow plug 7 in the example shown can be designed so that in the event of flame detection and a steep increase in the resistance of the glow element or the filament 8 of the glow plug due to the PTC behavior, the glow operation of the glow plug 7 can be stopped by others To save energy for heating the glow element 8, since the ignition device 6 has already ignited the fuel mixture prepared on the evaporation burner 1. Even if the glow plug 7 is then switched off, the flame monitoring, based on the PTC behavior of the glow element 8, can also be continued during the firing operation of the heater, in which the current signal to be applied to the glow plug 7 is maintained continuously or in a clocked manner. Thus, the flame formation in the combustion chamber 4 can also be detected during the combustion operation via the control circuit and a downstream evaluation device.
- FIG. 2 As an essential difference from FIG. 1, an ignition device 6 is shown, which has an open glow element, such as an incandescent filament 8 ', which is not embedded in a ceramic mass, but is exposed in the combustion chamber 4.
- an open glow element such as an incandescent filament 8 '
- the control functions explained above are also carried out here.
- the electrical energy to be kept constant at the ignition device 6 can also be changed and controlled if the change in resistance of the glow element or the filament 8 'is evaluated in a corresponding manner due to the PTC behavior.
- a corresponding control can of course also be carried out in the embodiment shown in FIG.
- the invention is not limited to the example shown.
- a burner design other than the evaporation burner 1 shown can also be used in such a heater.
- the glow element need not be designed in the form of an incandescent filament 8, 8 ', but the glow element can have any shape that is suitable for the respective application, such as band-shaped, serpentine or the like.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Combustion (AREA)
Description
Die Erfindung befaßt sich mit einer Zündeinrichtung für ein brennstoffbetriebenes Fahrzeugzusatzheizgerät, gemäß dem Oberbegriff des Patentansprüchs 1The invention relates to an ignition device for a fuel-operated auxiliary vehicle heater according to the preamble of patent claim 1
Aus der JP-A- 1 244 215 und dem dazugehörigen Patent Abstract of Japan, vol. 13, no. 582 (M-911) (3930) ist eine gattungsgemäße Zündeinrichtung bekannt. Nach erfolgtes Zündung wird dort eine Keramik-Glühkerze an einen speziellen Flammüberwachungs-Schaltkreis geschaltet, wobei die Spannung an der Glühkerze mit einer Referenzspannung einer Spannungsquelle verglichen wird. Sowohl für den Zündvorgang als auch für die laufende Überwachung des Verbrennungsvorgangs besteht bei einer solchen Anordnung ein erhebliches Energiebedarf. Das Energieangebot einer Fahrzeugbatterie ist insbesondere bei niedrigen Außentemperaturen begrenzt, wodurch bei einem Einsatz des bekannten Anordnung zu Vorheizzwecken in einem Fahrzeug entweder die Vorheizdauer stark begrenzt wird oder ein nachfolgender Startvorgang des Fahrzeugmotors erschwert wird.From JP-A-1 244 215 and the associated patent Abstract of Japan, vol. 13, no. 582 (M-911) (3930) a generic ignition device is known. After the ignition has taken place, a ceramic glow plug is connected to a special flame monitoring circuit, the voltage at the glow plug being compared with a reference voltage from a voltage source. With such an arrangement, there is a considerable energy requirement both for the ignition process and for the ongoing monitoring of the combustion process. The energy supply of a vehicle battery is particularly limited at low outside temperatures, so that when the known arrangement is used for preheating purposes in a vehicle, either the preheating time is greatly limited or a subsequent starting process of the vehicle engine is made more difficult.
In der DE-A-37 06 555 ist als Zündeinrichtung für ein brennstoffbetriebenes Heizgerät eine Stabglühkerze vorgesehen, bei der der als Glühelektrode dienende Glühstab zugleich eine Ionisationselektrode bildet, die zur Flammüberwachung dient.In DE-A-37 06 555, a rod glow plug is provided as the ignition device for a fuel-operated heating device, in which the glow rod serving as the glow electrode also forms an ionization electrode, which is used for flame monitoring.
Hierdurch erhält man eine Flammüberwachungseinrichtung, welche thermisch unempfindlich ist, schnell anspricht und kostengünstig hinsichtlich der Herstellung ist. Hierzu ist bei einer Stabglühkerze ein Schutzrohr vorgesehen, welches die Ionisationselektrode bildet. Wenn man die Stabglühkerze zur Flammüberwachung unter Ausnutzung des Ionisationsprinzips nutzt, müssen zusätzliche Einrichtungen an der Stabglühkerze vorgesehen werden, welche als Ionisationselektrode zur Flammüberwachung wirken. Daher muß die sonst übliche Auslegungsform einer Stabglühkerze abgeändert werden und es muß eine speziell für die Ionisationsflammüberwachung geeignete Stabglühkerze hergestellt werden.This gives a flame monitoring device which is thermally insensitive, responds quickly and is inexpensive to manufacture. For this purpose, a protective tube is provided in the case of a glow plug, which forms the ionization electrode. If the rod glow plug is used for flame monitoring using the ionization principle, additional devices must be provided on the rod glow plug, which act as an ionization electrode for flame monitoring. Therefore, the usual design of a glow plug must be changed and a glow plug especially suitable for ionization flame monitoring must be manufactured.
Aus DE-A-32 31 781 ist eine Glühkerze für Brennkraftmaschinen bekannt, welche als Stabglühkerze ausgebildet ist. Diese Glühkerze besitzt einen Keramikträger, auf welchem ein leiterbahnähnliches Heizelement aufgebracht ist. Die dort beschriebene Ausführungsform einer Glühkerze eignet sich auch für ein Anordnen eines Überhitzungsschutzes (PTC-Widerstand) und/oder eines Spannungsbegrenzers (Varistors) in den Anschlußleitern des Heizelements. Eine Flammüberwachung erfolgt hierbei nicht.From DE-A-32 31 781 a glow plug for internal combustion engines is known, which is designed as a rod glow plug. This glow plug has a ceramic carrier on which a heating element similar to a conductor track is applied. The embodiment of a glow plug described there is also suitable for arranging an overheating protection (PTC resistor) and / or a voltage limiter (varistor) in the connecting leads of the heating element. There is no flame monitoring.
Ferner ist es bei brennstoffbetriebenen Heizgeräten, insbesondere Fahrzeugzusatzheizgeräten, üblich, zusätzlich zu einer Zündeinrichtung, wie einer Stabglühkerze, einen Flammwächter als Flammwächtereinrichtung vorzusehen, welcher in die Brennkammer des Heizgerätes ragt. Derartige Flammwächter stören nicht nur die Flammenbildung in der Brennkammer, sondern sind auch sehr störungsempfindlich, da sie im Brennbetrieb sich immer in der Flammenzone befinden müssen.Furthermore, in the case of fuel-operated heating devices, in particular vehicle auxiliary heating devices, in addition to an ignition device such as a rod glow plug, it is customary to provide a flame detector as a flame detector device, which protrudes into the combustion chamber of the heater. Such flame monitors not only interfere with the flame formation in the combustion chamber, but are also very sensitive to faults, since they must always be in the flame zone during combustion.
In DE-A-28 02 625 und 26 41 274 sind Glühzündeinrichtungen angegeben, bei denen PTC-Widerstände als Überhitzungsschutz eingesetzt werden, wobei in der zweitgenannten Druckschrift der Betriebszustand über das optische Glühbild bei einer Glühdrahtzündeinrichtung mit PTC-Widerstand erfaßt werden kann.DE-A-28 02 625 and 26 41 274 are glow ignition devices specified, in which PTC resistors are used as protection against overheating, the operating state in the second-mentioned publication being able to be detected via the optical glow pattern in a filament ignition device with a PTC resistor.
Aus DE-A-27 43 325 läßt sich ein Kanalheizer entnehmen, der eine Temperatursteuerung bzw. Temperaturbegrenzung unter Verwendung von Heißleitern hat.From DE-A-27 43 325 a duct heater can be seen which has a temperature control or temperature limitation using thermistors.
Der Erfindung liegt die Aufgabe zugrunde, eine Zündeinrichtung für ein brennstoffbetriebenes Heizgerät der gattungsgemäßen Art bereitzustellen, mittels der ein energiesparendes Zünden und eine zuverlässige Flammüberwachung ohne zusätzliches Flammwächterbauteil ermöglicht wird.The invention has for its object to provide an ignition device for a fuel-operated heater of the generic type, by means of which energy-saving ignition and reliable flame monitoring is made possible without an additional flame detector component.
Diese Aufgabe wird durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst. Nach der Erfindung zeichnet sich eine Zündeinrichtung für ein brennstoffbetriebenes Fahrzeugzusatzheizgerät zum einen dadurch aus, daß das Glühelement ein PTC-Verhalten aufweist, sodaß sich dessen Widerstand bei der Flammenbildung zusätzlich erhöht.This object is achieved by the characterizing features of patent claim 1. According to the invention, an ignition device for a fuel-operated auxiliary vehicle heater is distinguished on the one hand by the fact that the glow element has a PTC behavior, so that its resistance to flame formation is additionally increased.
Bei der erfindungsgemäßen Zündeinrichtung wird somit das PTC-Verhalten des Glühelements, wie beispielsweise eines Wolframglühelements, genutzt, um eine Flammüberwachung während des Glühvorgangs und auch später vorzunehmen. Bei einem Material mit PTC-Verhalten nimmt der Widerstand mit steigender Temperatur des Materials zu.In the ignition device according to the invention, the PTC behavior of the glow element, such as a tungsten glow element, is thus used to carry out flame monitoring during the glow process and also later. For a material with PTC behavior, the resistance increases with the temperature of the material.
Dieser Temperaturbereich ist bei der erfindungsgemäßen Zündeinrichtung so gewählt, daß dann, wenn sich eine Flamme in der Brennkammer des Heizgerätes bildet, der Widerstand des Glühelements gegenüber dem Glühvorgang der Zündeinrichtung ansteigt und hierbei ein steiler Anstieg des Widerstandes des Glühelements zu verzeichnen ist. Als bevorzugtes Material für das Glühelement hat sich Wolfram erwiesen, welches ein PTC-Verhalten hat, wenn man eine Stabglühkerze als Zündeinrichtung vorsieht. Somit kann bei der erfindungsgemäßen Zündeinrichtung die Flammüberwachung ohne zusätzliche Maßnahmen an der Glühkerze oder einem zusätzlichen Bauteil, wie einem Flammwächter, erfolgen, so daß die Flammenbildung in der Brennkammer nicht durch in die Brennkammer ragende zusätzliche Bauteile gestört wird. Zum anderen entfällt auch ein Bauteil bei einem Brenner eines brennstoffbetriebenen Heizgeräts, wodurch sich die Herstellung desselben vereinfacht und sich die Brennerabmessungen des Heizgerätes verkürzen lassen.This temperature range is in the invention Ignition device selected so that when a flame forms in the combustion chamber of the heating device, the resistance of the glow element to the glow process of the ignition device increases and a steep increase in the resistance of the glow element is recorded. Tungsten has proven to be the preferred material for the glow element, which has a PTC behavior if a rod glow plug is provided as the ignition device. Thus, in the ignition device according to the invention, the flame monitoring can take place without additional measures on the glow plug or an additional component, such as a flame monitor, so that the flame formation in the combustion chamber is not disturbed by additional components protruding into the combustion chamber. On the other hand, there is also no component in a burner of a fuel-operated heating device, which simplifies the manufacture of the same and can shorten the burner dimensions of the heating device.
Zum zweiten wird zur Erfassung des Spannungsabfalls aufgrund der bei der Flammenbildung zusätzlich auftretenden Widerstandserhöhung an das Glühelement ein konstanter Strom angelegt. Mittels einer solchen Schaltung kann beispielsweise eine Flammüberwachung erfolgen, da bei einer Flammenbildung durch die erhöhte Temperatur an dem Glühelement der Widerstand derselben plötzlich ansteigt und hierdurch ein Spannungsabfall beim Anliegen eines konstanten Stromes auftritt, der dann zur Auswertung bei einer Steuereinrichtung des Heizgerätes über entsprechende Signalverarbeitungseinrichtungen genutzt werden kann, um entsprechende Schaltvorgänge auszulösen, wenn sich eine Flamme in der Brennkammer des Heizgerätes gebildet hat. Dieser konstante Strom wird in den Glühpausen der Zündeinrichtung angelegt, die man beispielsweise dann erhält, wenn man die Glühzündeinrichtung mittels eines Glühtaktrelais ansteuert. Daher sind bei der erfindungsgemäßen Auslegung der Zündeinrichtung im wesentlichen nur schaltungstechnische Maßnahmen im Hinblick auf die Verwirklichung einer Flammüberwachung zu treffen, welche sich in die Steuereinrichtung des Heizgerätes integrieren lassen. Hierdurch verringert sich der Bauteilaufwand bei der Herstellung eines solchen Heizgerätes.Secondly, a constant current is applied to the glow element in order to detect the voltage drop due to the additional increase in resistance that occurs during flame formation. Such a circuit can be used for flame monitoring, for example, because when a flame is formed due to the increased temperature on the glow element, the resistance of the glow element suddenly increases and a voltage drop occurs when a constant current is applied, which is then used for evaluation by a control device of the heater via appropriate signal processing devices can be used to trigger appropriate switching operations when a flame has formed in the combustion chamber of the heater. This constant current is applied in the glow pauses of the ignition device, which is obtained, for example, when the glow ignition device is controlled by means of a glow contact relay. Therefore, in the design according to the invention the ignition device essentially only to take circuitry measures with regard to the implementation of flame monitoring, which can be integrated into the control device of the heater. This reduces the amount of components involved in the manufacture of such a heater.
Drittens ist nach der Erfindung die Zündeinrichtung so ausgelegt, daß beim Auftreten eines zusätzlichen Widerstandsanstieges des Glühelements, d.h. während der Flammüberwachung mittels der Zündeinrichtung, eine Abschaltung des Glühbetriebes der Glühzündeinrichtung ausgelöst wird, da nunmehr eine Flamme in der Brennkammer zur Aufnahme des Brennbetriebes des Heizgerätes vorhanden ist. Somit kann man unter Ausnutzung des PTC-Verhaltens des Glühelements auch die Zündeinrichtung selbsttätig abschalten.Third, according to the invention, the ignition device is designed such that when an additional resistance increase of the glow element occurs, i.e. during flame monitoring by means of the ignition device, a shutdown of the glow operation of the glow ignition device is triggered, since a flame is now present in the combustion chamber for starting the burner operation of the heater. Thus, the ignition device can also be switched off automatically by utilizing the PTC behavior of the glow element.
Auch gestattet die erfindungsgemäße Auslegung der Zündeinrichtung eine ständige Überwachung des Brennbetriebes, wenn man das Stromsignal an die Zündeinrichtung konstant oder getaktet anlegt, so daß man eine ständige Flammüberwachung auch während des Betriebes des Heizgerätes vornehmen kann. Das Stromsignal kann vorzugsweise wesentlich kleiner als das für den eigentlichen Glühbetrieb erforderliche sein.The design of the ignition device according to the invention also permits constant monitoring of the combustion operation if the current signal to the ignition device is applied in a constant or clocked manner, so that continuous flame monitoring can also be carried out while the heater is in operation. The current signal can preferably be significantly smaller than that required for the actual glow operation.
Bei der erfindungsgemäßen Zündeinrichtung kann somit die Flammüberwachung sowohl in der Glühphase der Glühzündeinrichtung, wenn sie ihren bestimmungsgemäßen Zweck als Zündeinrichtung verfolgt, als auch beim Brennbetrieb genutzt werden, so daß das Brennverhalten mittels entsprechenden Auswertungen erfaßt und überwacht werden kann.In the ignition device according to the invention, the flame monitoring can thus be used both in the glow phase of the glow ignition device, if it is used for its intended purpose as an ignition device, and in the combustion mode, so that the combustion behavior can be detected and monitored by means of appropriate evaluations.
Um einen besonders energiesparenden Betrieb der Zündeinrichtung zu ermöglichen, kann die der Zündeinrichtung zugeführte Energie herabgesetzt werden, wenn durch die Flammenbildung die Zündeinrichtung erwärmt wird und daher der elektrische Energiebedarf zur Konstanthaltung der Temperatur der Zündeinrichtung geringer ist. Die jeweiligen Größen sind hierbei bauteilspezifisch.To ensure particularly energy-saving operation of the ignition device enable, the energy supplied to the ignition device can be reduced if the ignition device is heated by the flame formation and therefore the electrical energy requirement for keeping the temperature of the ignition device constant is lower. The respective sizes are component-specific.
Gemäß einer weiteren Ausgestaltungsform wird die Zündeinrichtung abgeschaltet, wenn die aufgrund des PTC-Verhaltens des Glühelements ermittelte Energiebedarfsabnahme einen vorbestimmten Vorgabewert unterschreitet. Als bevorzugte Ausführungsform läßt sich als Zündeinrichtung eine Stabglühkerze einsetzen, welche ein in eine Keramikmasse eingebettetes Glühelement, wie eine Glühwendel, hat. Für das Glühelement oder die Glühwendel kommt als Material insbesondere Wolfram in Betracht, das ein ausgeprägtes PTC-Verhalten hat.According to a further embodiment, the ignition device is switched off when the decrease in energy consumption determined on the basis of the PTC behavior of the glow element falls below a predetermined preset value. As a preferred embodiment, a stick glow plug can be used as the ignition device, which has a glow element, such as a filament, embedded in a ceramic mass. Tungsten, which has a pronounced PTC behavior, is particularly suitable as the material for the glow element or the filament.
Die Erfindung wird nachstehend anhand von bevorzugten Ausführungsformen unter Bezugnahme auf die Zeichnung näher erläutert. Darin zeigt:
- Fig. 1
- eine schematische Ansicht einer bevorzugten Ausführungsform einer Zündeinrichtung für ein brennstoffbetriebenes Heizgerät, und
- Fig. 2
- eine Ausführungsvariante mit einer anderen Zündeinrichtung.
- Fig. 1
- a schematic view of a preferred embodiment of an ignition device for a fuel-operated heating device, and
- Fig. 2
- an embodiment variant with another ignition device.
Zur Verdeutlichung der Erfindung ist in den Figuren nur ein Brennerbereich eines Heizgerätes jeweils gezeigt. Bei den dargestellten Beispielen wird der Brenner von einem Verdampfungsbrenner 1 gebildet, der einen saugfähigen Körper 2, wie ein Vlies, auf einem Träger hat, der in einem Brennrohr 3 angeordnet ist, das eine Brennkammer 4 begrenzt. Über eine Brennstoffzuleitung 5 wird dem Verdampfungsbrenner 1 flüssiger Brennstoff zugeführt. Als eine insgesamt mit 6 bezeichnete Zündeinrichtung ist in Figur 1 eine Stabglühkerze 7 vorgesehen, die durch den Träger und den saugfähigen Körper 2 des Verdampfungsbrenners 1 geht und in die Brennkammer 4 ragt. Die Stabglühkerze 7 hat als Glühelement beispielsweise eine Glühwendel 8, die vorzugsweise aus Wolfram besteht und die in eine Keramikmasse 9 eingebettet ist. Mittels eines Glühtaktrelais oder Transistors wird die Stabglühkerze 7 in der Glühphase so betrieben, daß das in die Keramikmasse 9 eingebettete Glühelement 8, wie die Glühwendel als Glühelement dient, so daß die Stabglühkerze 7 auf eine für die Zündung des am Verdampfungsbrenners 1 aufbereiteten Luft/Brennstoff-Gemisches geeignete Temperatur erwärmt wird. Diese geeignete Temperatur oder Soll-Temperatur liegt etwa in der Größenordnung von 1100°C. Während der Glühpausen, d.h. der Taktpausen eines Glühtaktrelais 10, wird ein konstanter Strom I an das Glühelement 8 der Stabglühkerze 7 angelegt. Wenn in der Brennkammer 4 sich ein Flamme ausgebildet hat, wird die Stabglühkerze 7 und somit das Glühelement bzw. die Glühwendel 8 derselben zusätzlich durch die Flammentemperatur erwärmt, und aufgrund des PTC-Verhaltens des Glühelements 8 steigt deren Widerstand zusätzlich an. Durch diesen zusätzlichen Widerstandsanstieg wird ein Spannungsabfall in dem Leitungsabschnitt mit konstantem Strom erzeugt, der zur Flammüberwachung genutzt wird. Über eine nicht näher dargestellte Auswerteeinrichtung kann dann dieser Spannungsabfall genutzt werden, um über eine nicht näher dargestellte Steuereinrichtung des Heizgerätes entsprechende Schaltvorgänge auszulösen. Auch wenn dieser Spannungsabfall nicht auftritt und sich daher keine Flamme in der Brennkammer 4 ausgebildet hat, können entsprechende Schaltvorgänge wie bei einem üblichen zusätzlichen Flammwächter ausgelöst werden.To clarify the invention, only one burner area of a heater is shown in each case in the figures. In the examples shown, the burner is formed by an evaporation burner 1, which has an
Eine Ansteuerschaltung 11 der Stabglühkerze 7 bei dem dargestellten Beispiel kann so ausgelegt werden, daß bei einer Flammerkennung und eines steilen Anstieges des Widerstandes des Glühelements bzw. der Glühwendel 8 der Stabglühkerze aufgrund des PTC-Verhaltens der Glühbetrieb der Stabglühkerze 7 gestoppt werden kann, um weitere Energie zum Aufheizen des Glühelements 8 einzusparen, da nämlich bereits die Zündeinrichtung 6 das am Verdampfungsbrenner 1 aufbereitete Brenngemisch gezündet hat. Selbst wenn die Stabglühkerze 7 dann abgeschaltet ist, kann die Flammüberwachung, basierend auf dem PTC-Verhalten des Glühelements 8 auch während des Brennbetriebes des Heizgerätes fortgesetzt werden, in dem das an die Stabglühkerze 7 anzulegende Stromsignal ständig oder getaktet aufrechterhalten wird. Somit kann man über die Ansteuerschaltung und einer nachgeordneten Auswerteinrichtung die Flammbildung in der Brennkammer 4 auch während des Brennbetriebes erfassen.A control circuit 11 of the
Bei der in Figur 2 dargestellten Variante sind gleiche oder ähnliche Teile mit denselben Bezugszeichen wie in Figur 1 versehen und werden daher nicht nochmals erläutert. In Figur 2 ist als wesentlicher Unterschied zu Figur 1 eine Zündeinrichtung 6 gezeigt, die ein offenes Glühelement, wie eine Glühwendel 8' hat, die nicht in eine Keramikmasse eingebettet ist, sondern in der Brennkammer 4 freiliegt. Die voranstehend erläuterten Steuerfunktionen werden auch hierbei durchgeführt. Ferner kann auch die zur Temperaturkonstanthaltung an der Zündeinrichtung 6 aufzuwendende elektrische Energie geändert und gesteuert werden, wenn die Widerstandsänderung des Glühelements bzw. der Glühwendel 8' aufgrund des PTC-Verhaltens in entsprechender Weise ausgewertet wird. Eine entsprechende Steuerung läßt sich natürlich auch bei der in Figur 1 gezeigten Ausführungsform vornehmen.In the variant shown in FIG. 2, the same or similar parts are provided with the same reference numerals as in FIG. 1 and are therefore not explained again. In FIG. 2, as an essential difference from FIG. 1, an ignition device 6 is shown, which has an open glow element, such as an incandescent filament 8 ', which is not embedded in a ceramic mass, but is exposed in the
Selbstverständlich ist die Erfindung nicht auf das dargestellte Beispiel beschränkt. Auch kann eine andere Brennerbauform als ein dargestellter Verdampfungsbrenner 1 bei einem solchen Heizgerät verwendet werden. Insbesondere braucht das Glühelement nicht in Form einer Glühwendel 8, 8' ausgelegt zu sein, sondern das Glühelement kann irgendeine beliebige und für den jeweiligen Anwendungszweck geeignete Gestalt, wie bandförmig, schlangenförmig oder dergleichen, haben.Of course, the invention is not limited to the example shown. A burner design other than the evaporation burner 1 shown can also be used in such a heater. In particular, the glow element need not be designed in the form of an
Claims (9)
- An ignition system for a fuel-operated auxiliary vehicle heater, with a control means (11) for supplying current to at least one heater element (8), the ignition system (6) serving at the same time as a flame-monitoring means, characterised in that the heater element (8) has a PTC characteristic behaviour so that its resistance increases additionally upon flame formation and in that by means of the control arrangement the heating operation of the ignition system (6) is shut down after an additional increase in the resistance of the heating element (8) and in that, during its heating pauses, a constant current is applied by means of an evaluating device to the ignition system (6) in order to detect a voltage drop in the heating element (8).
- An ignition system according to Claim 1, characterised in that for further flame-monitoring in combustion mode, the current signal remains applied to the ignition system (6).
- An ignition system according to Claim 2, characterised in that the current signal is substantially less than is necessary for actual heating operation.
- An ignition system according to Claim 2 or 3, characterised in that the current signal remains periodically and briefly applied.
- An ignition system according to one of the preceding Claims, characterised in that the electrical energy to be fed to the heating element (8) is diminished according to the dictates of the energy required to maintain a constant temperature to a level specific for the component and on a basis of the PTC behaviour of the ignition system (6).
- An ignition system according to Claim 5, characterised in that when the electrical energy to be fed to the heating element (8) drops below a predetermined value, the ignition system (6) is switched off.
- An ignition system according to one of the preceding Claims, characterised in that the ignition system (6) is constructed in the from of a rod-shaped glow plug (7) with a heater element (8) embedded in a ceramic composition (9).
- An ignition system according to Claim 7, characterised in that the heater element (8) consists of tungsten.
- An ignition system according to Claim 7 or 8, characterised in that the heater element is constructed as a glow filament (8).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4015097A DE4015097C1 (en) | 1990-05-11 | 1990-05-11 | |
| DE4015097 | 1990-05-11 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0456245A2 EP0456245A2 (en) | 1991-11-13 |
| EP0456245A3 EP0456245A3 (en) | 1992-02-19 |
| EP0456245B1 true EP0456245B1 (en) | 1995-01-18 |
Family
ID=6406161
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP91107574A Expired - Lifetime EP0456245B1 (en) | 1990-05-11 | 1991-05-10 | Ignition system for a heater using a fuel |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0456245B1 (en) |
| DE (2) | DE4015097C1 (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4446113C5 (en) * | 1994-12-22 | 2008-08-21 | J. Eberspächer GmbH & Co. KG | Ignition device for heaters |
| DE19527873C2 (en) * | 1995-07-29 | 2001-09-13 | Eberspaecher J Gmbh & Co | Device for generating and igniting a fuel vapor-air mixture |
| WO1997038223A1 (en) * | 1996-04-10 | 1997-10-16 | Denso Corporation | Glow plug, its production process and ion current detector |
| DE19622126C2 (en) * | 1996-06-01 | 2003-01-16 | Webasto Thermosysteme Gmbh | Method for ignition and / or flame monitoring in a vehicle heater |
| DE19625823C2 (en) * | 1996-06-28 | 1998-07-02 | Webasto Thermosysteme Gmbh | Flame monitoring method for a vehicle heater |
| JP3605965B2 (en) * | 1996-09-12 | 2004-12-22 | 株式会社デンソー | Glow plug |
| JP3796846B2 (en) * | 1996-09-12 | 2006-07-12 | 株式会社デンソー | Glow plug |
| DE19702339C2 (en) * | 1996-11-29 | 1998-12-03 | Webasto Thermosysteme Gmbh | Method for checking the function of a glow element used as a flame detector |
| DE19649473C2 (en) * | 1996-11-29 | 1999-01-07 | Webasto Thermosysteme Gmbh | Method of monitoring the flame in a fuel powered heater |
| EP0845638B1 (en) * | 1996-11-29 | 2004-10-20 | WEBASTO THERMOSYSTEME GmbH | Ignition system for a fuel fired heater |
| DE19709091C1 (en) * | 1997-03-06 | 1998-05-14 | Honeywell Bv | Flame monitoring circuit for gas burner |
| DE19813313A1 (en) * | 1998-03-26 | 1999-04-15 | Bosch Gmbh Robert | Control method for premixing type gas burner |
| DE19936729C1 (en) * | 1999-08-06 | 2000-11-16 | Webasto Thermosysteme Gmbh | Glow plug control method for ignition of automobile heating device uses measured electrical resistance across glow plug for controlling clocked voltage supplied to glow plug during ignition phase |
| DE10025953C2 (en) * | 2000-05-26 | 2002-04-18 | Webasto Thermosysteme Gmbh | Method for driving a glow plug to ignite a vehicle heater |
| DE10059846C2 (en) * | 2000-11-30 | 2003-03-20 | Webasto Thermosysteme Gmbh | Ignition element for igniting fuel in atomizer burners |
| DE10140972B4 (en) * | 2001-08-27 | 2009-05-07 | Webasto Ag | Method and system for operating a vehicle heater |
| DE10162321A1 (en) * | 2001-12-18 | 2003-07-10 | Nanogate Technologies Gmbh | flame monitoring |
| DE10223948C1 (en) * | 2002-05-29 | 2003-06-12 | Webasto Thermosysteme Gmbh | Spark ignition for motor vehicle combustion heater has a glow plug with two resistances operating in parallel or series depending on switching |
| DE10249872B4 (en) * | 2002-10-25 | 2017-03-02 | Webasto Ag | Mobile fuel heater with a glow plug / flame guard |
| DE10311898B4 (en) * | 2003-03-18 | 2005-04-21 | Webasto Ag | Heater for a vehicle |
| DE102004038011B3 (en) * | 2004-08-04 | 2006-05-11 | Webasto Ag | Incandescence device for auxiliary heating device of vehicle, has control unit with input voltage signal having specific clock frequency and providing current with saw tooth function for incandescence unit |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2641274C3 (en) * | 1976-09-14 | 1979-08-23 | Jenaer Glaswerk Schott & Gen., 6500 Mainz | Safety device for gas-heated, transparent glass ceramic cooking surfaces |
| DE2743325C2 (en) * | 1976-10-29 | 1982-05-27 | Backer Elektro-Vaerme Ab, Soesdala | Electric air heating system |
| DE2802625C3 (en) * | 1978-01-21 | 1985-07-18 | BERU Ruprecht GmbH & Co KG, 7140 Ludwigsburg | Glow plug |
| DE3607574A1 (en) * | 1986-03-07 | 1987-09-10 | Rudolf Schreiner | Starting device for auxiliary heaters with wick burners |
| DE3706555A1 (en) * | 1986-07-18 | 1988-01-21 | Webasto Werk Baier Kg W | Ignition arrangement for a fuel-operated heating device |
| JPH01244215A (en) * | 1988-03-24 | 1989-09-28 | Nippon Denso Co Ltd | Combustion device |
| DE3932602C1 (en) * | 1989-09-29 | 1990-04-26 | Schoeller & Co Elektrotechnische Fabrik Gmbh & Co, 6000 Frankfurt, De |
-
1990
- 1990-05-11 DE DE4015097A patent/DE4015097C1/de not_active Expired - Fee Related
-
1991
- 1991-05-10 EP EP91107574A patent/EP0456245B1/en not_active Expired - Lifetime
- 1991-05-10 DE DE59104287T patent/DE59104287D1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE4015097C1 (en) | 1991-04-11 |
| EP0456245A2 (en) | 1991-11-13 |
| EP0456245A3 (en) | 1992-02-19 |
| DE59104287D1 (en) | 1995-03-02 |
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